• Frightful Presence: Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

• Acid Breath (Recharge 5-6): The dragon exhales acid in a 90-foot line that is 10 feet wide. Each creature in that line must make a DC 22 Dexterity saving throw, taking 67 (15d8) acid damage on a failed save, or half as much damage on a successful one.

Legendary Actions

The ancient black dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature's turn. The ancient black dragon regains spent legendary actions at the start of its turn.

• Detect: The dragon makes a Wisdom (Perception) check.

• Tail Attack: The dragon makes a tail attack.

• Wing Attack (Costs 2 Actions): The dragon beats its wings. Each creature within 15 ft. of the dragon must succeed on a DC 23 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.